The fish that did hatch in these waters with high quantities of micro-plastics were “smaller, slower, and more stupid” than those that hatched in clean waters, lead author Dr Oona Lonnstedt, from Uppsala University, said.When exposed to predators, about half the young perch from clean waters survived for 24 hours. Those that had been raised with the strongest plastic concentrations were all consumed by pike over the same period.

Most surprising for the research team was the way that plastic changed food preferences.

“They all had access to zooplankton and yet they decided to just eat plastic in that treatment. It seems to be a chemical or physical cue that the plastic has, that triggers a feeding response in fish,” Dr Lonnstedt told BBC News. “They are basically fooled into thinking it’s a high-energy resource that they need to eat a lot of. I think of it as unhealthy fast food for teenagers, and they are just stuffing themselves.”